The present invention relates generally to lenses and pertains particularly to microwave lenses and method of making the same.
Lenses are typically constructed by selecting a body of material having the appropriate dielectric constant and shaping or forming a body of the material into the desired configuration. Materials having the appropriate, dielectric constant for microwaves are typically fairly heavy and are generally unsuitable for use on airframes wherein weight is a major consideration. In addition, the process of forming such lenses is time consuming and expensive.
Another approach to the construction of lenses for microwave usage is disclosed in U.S. Pat. No. 2,716,190 issued Aug. 23, 1955 to E. B. Baker. This patent discloses the construction of microwave lenses from a material of styrene foam having particles of magnesium or aluminum embedded therein. The aluminum and magnesium particles are in the form of rods, spheres or planes with rods and spheres being preferred.
Another patent which is of interest in connection with the construction of microwave lenses is U.S. Pat. No. 3,129,191 issued Apr. 14, 1964 to Nickerson et al. This patent discloses the construction of dielectric foam materials for making microwave lenses. This patent discloses the polypoxide resin foams having aluminum powder therein as a filler for adjusting the dielectric constant.
Other patents of interest in connection with the subject invention are as follows:
U.S. Pat. No. 2,923,934 entitled "Method and Means For Minimizing Reflection of High Frequency Radio Waves", issued Feb. 2, 1960 to Halpern.
U.S. Pat. No. 2,954,552 entitled "Reflecting Surface and Microwave Absorption Layer", issued Sept. 27, 1960 to Halpern.
U.S. Pat. No. 3,079,289 entitled "High Dielectric Constant Material and Method of Making Same", issued Feb. 26, 1963 to George Jr. et al.
While various methods and means of making microwave lenses are known, it is desirable that more effective lightweight and inexpensive lenses be available.